The rise and crash of civilizations | Gene Expression

![480px-Montagem_Brasilia][1]One of the questions of interest in the study of the evolution of culture is whether there is a direction in history in terms of complexity. As I [have noted before][2] in the pre-modern era **many felt that the direction of history was of decline.** That is, the ancients were wise and subtle beyond compare and comprehension. In contrast, in our era of rapid and boisterous technological innovation and economic growth we tend toward a [“Whiggish”][3] model, where the future is gleaming with potential and possibility. But we live in a peculiar time. The reality is that for most of history for most people **there was very little change from generation to generation.** [Malthus][4] reigned supreme. Values were timeless, and quality of life was unchanging.

There were exceptions. [Theodore of Tarsus][5] was born in the year 602, in Cilicia in southern Turkey, a subject of the Byzantine Emperor [Phocas][6]. It is Phocas to whom we can offer thanks for the preservation of the [Pantheon][7] of Rome down to the modern age (he sponsored its transformation into a Christian church). In his youth Theodore became a subject of the Sassanid Persians, who ruled Cilicia for a time before it was brought back under Byzantine rule thanks to the efforts of [Heraclius][8]. Eventually in adulthood he fled the armies of the Muslim Arabs, who conquered Cilicia, and relocated to Constantinople and then Rome. After Rome Theodore eventually settled in to a position as Archbishop of Canterbury, amongst the newly converted English. Theodore of Tarsus lived life at a “hinge of history,” when much changed in understanding of how the world was ordered (though to be honest there is a great deal of evidence that many Christians viewed Islam and the Arabs as but a momentary interruption until the 8th century). But he was very much an exception. In his longevity, his position as a literate man of power, and the radical shifts in the elite culture of his time. In the year of Theodore’s birth the English were a pagan people, and the Near East was staunchly Christian. At his death the English were a stoutly Christian people, and the Near East was crystallizing into what we now term the Islamic World.

[![][9]][10]Theodore gives us a specific personalized window into the coarse general dynamics through which history flows. History is a dynamic _of _people, but also operates _upon _people. A new paper in _Nature _illustrates the insights we may gain from abstraction and formalization of these dynamics. It is a lens upon history which is more crisply analytic and potentially more robust in inferential power, though of course far less rich in gripping narrative. [Rise and fall of political complexity in island South-East Asia and the Pacific][11]:

> There is disagreement about whether human political evolution has proceeded through a sequence of incremental increases in complexity, or whether larger, non-sequential increases have occurred. The extent to which societies have decreased in complexity is also unclear. These debates have continued largely in the absence of rigorous, quantitative tests. We evaluated six competing models of political evolution in Austronesian-speaking societies using phylogenetic methods. **Here we show that in the best-fitting model political complexity rises and falls in a sequence of small steps. This is closely followed by another model in which increases are sequential but decreases can be either sequential or in bigger drops. **The results indicate that large, non-sequential jumps in political complexity have not occurred during the evolutionary history of these societies. This suggests that, despite the numerous contingent pathways of human history, there are regularities in cultural evolution that can be detected using computational phylogenetic methods.

![800px-Gate_to_Prambanan_complex][12]The guts of the paper are really in the [supplements][13]. The short of it is that the authors used a phylogenetic framework and statistical methods to smoke out which models were the best fit for how patterns of social complexity mapped onto the branches of the Austronesian language family. The Austronesians are a group whose ethnognesis is understood to a great extent, and, who have expanded across a wide variety of ecologies in the recent past. They range from Madagascar to Easter Island, two points between which the distance is shorter traversing Africa and South America, rather than the Indian and Pacific oceans. In terms of complexity you also have singular groups situated upon Polynesian atolls, all the way up to the complex civilizations of the Javanese, whose polities sometimes spanned the whole breadth of the modern Indonesian archipelago.

There are four rough types of societies being analyzed in terms of their category of complexity. You can see them in figure 3, as well as the stylized model of shifts from one level of social complexity to another:


“Acephalous” means that there’s no level of leadership above the local one. So the clan chief presumably does not report to a superior. “Simple chiefdom” means that there’s a level above the clan chief. “Complex chiefdom” has another level above again. And the state means that there’s a subsequent level, or more.

![complex2][15]As noted in the abstract they found that a step-wise incremental move up and down the levels of complexity best explained the patterns across Austronesian peoples which we see today. That is, complex ancestral societies may have devolved toward simpler organizational patterns, and simple ancestral societies may have given rise to complex ones. This is the “unilinear” pattern; what goes up does so gradually, and what goes down does so gradually. Interestingly this model shows that history can go in cycles. Empires can rise and fall. Rome and Angkor are not aberrations. But the second most supported model was a “relaxed unilinear” one, whereby societies still accrue complexity in a gradual step-wise fashion,** but they _may_**** regress catastrophically**. In other words, they can potentially go from being of relatively large scale to much smaller scale, atomizing and shattering. I believe that this is probably the more interesting finding. It is not surprising that societies change in complexity in an ordered fashion, but that complex systems are fragile and can lose institutional structures in a cascade would have big theoretical implications.

Obviously this sort of study on one set of societies has limitations. What has Java to tell us of Japan? This is a survey of patterns among Austronesians, and one can’t guarantee that they’ll be generalizable. Despite the ecological variation across these societies, it is notable that they all had a strong maritime bias. Perhaps continental polities are subject to different dynamics. Additionally, there is some limitation in the level of aggregation and institutional complexity which we can see among Austronesians. Even at its height [Majapahit][16] lacked the force-projection power of Rome, Imperial China, or even the Arab Caliphates. **As a hypothesis I will hazard to guess that using a broader sample the relaxed unilinear model would be supported even more**. Imperial Rome and Han China squeezed their populations much more than Majapahit on the economic margin to support enormous central cultural complexes. Once the interlocking systems of deference and rent-seeking snapped the regression could be extreme.

We can see the utility of this sort of model after the fall of the Roman Empire. Some regions, such as Anatolia, Italy, Spain and southern Gaul, regressed only so much (at most down to the level of complex chiefdoms, but usually down to a looser state-level political structure). On the other hand, Britain and much of the interior of the Balkans seem to have regressed much further and lost all touch with the institutional power of Roman civilization. Anglo-Saxon England had dozens of “kings” when it reemerged into the light of history in the late 6th century. These were basically complex chiefdoms, likely successors to simple chiefdoms, not states. This implies that much of Britain had gone from being part of an empire, a higher order of organization and complexity than a typical state, to a region characterized by tribalism. Something similar happened in the Balkans with the removal of Roman troops with the invasion of the Avars in the late 6th century. Once the region comes back into the historical record most of the Latin-speaking populations are gone, replaced by Slavic tribes under the hegemony of Ugric and Turkic elites (and possibly Iranian, there is some supposition that the Croats and Serbs may originally have been Iranian tribes which were later subsumed by their Slavic vassals, just as the Bulgars later were). Multiple levels of structure had been swept away, and institutions such as organized Christian religion had to be reintroduced later.

Luckily for Dark Age Europe reservoirs of civilization persisted from which institutions could begin the recolonization process. Isolated societies such as the Maya or Angkor seem to have dissolved more fully. A civilization which lasts clearly needs a commonwealth of states.

**Citation:** Currie, Thomas E., Greenhill, Simon J., Gray, Russell D., Hasegawa, Toshikazu, & Mace, Ruth (2010). Rise and fall of political complexity in island South-East Asia and the Pacific Nature : [10.1038/nature09461][17]

_Image credit: Wikimedia Commons_


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